The product of the present invention, alkylated cyanoacetylurea, is a useful starting material of a 5-alkyl substituted uracil which is an important intermediate for producing a pharmaceutical agent (e.g., anti-HIV drug, antiviral agent and the like), agents for photographs (e.g., stabilizer of silver halide and the like), and the like.
As a prior art method for producing alkylated cyanoacetylurea, a method comprising condensing cyanoalkylacetic acid, urea and acetic anhydride by heating is known [Journal of the American Pharmaceutical Association, 44, 545 (1955)]. Cyanoalkylacetic acids (starting material) can be obtained by reacting an ester compound of cyanoacetic acid and alkyl halide. However, the reaction requires use of a dangerous reagent (e.g., sodium hydride and the like) in an anhydrous solvent, as well as hydrolysis of ester and subsequent neutralization with an acid for isolation of the product. The inorganic salt (e.g., sodium sulfate and the like) produced at this stage contaminates tools and the like used for the reaction and this method is disadvantageous for the production at a plant scale.
What is more, alkylated cyanoacetylurea cannot be obtained at a high yield by a production method comprising direct alkylation of cyanoacetylurea.
There is therefore a demand for an easy, convenient and industrially-utilizable method for producing alkylated cyanoacetylurea from a starting material that is easily obtainable.
It is therefore an object of the present invention to provide a method for an easy, convenient and industrially-utilizable method for producing alkylated cyanoacetylurea useful as a synthetic starting material of 5-alkyl substituted uracils from a starting material that is easily obtainable. Another object of the present invention is to provide a method for an easy, convenient and industrially-utilizable method for producing an alkylated cyanoacetylamino compound.